Swimming pool cover having reduced friction during slidable movement

ABSTRACT

A swimming pool cover for extension over and retraction from a swimming pool and where the cover may engage a portion of the deck surrounding the swimming pool during movement thereof. The swimming pool cover comprises a flexible fabric sheet of the type capable of being spooled or rolled and capable of being unrolled to extend over a swimming pool. The swimming pool cover is comprised of a sheet having a top surface and a bottom surface with the bottom surface extending over and potentially in contact with the upper surface of the water in the swimming pool. In order to reduce frictional effects between the bottom surface of the swimming pool cover and the upper surface of the deck, the swimming pool cover is provided with a surface configuration which is roughened to substantially reduce surface area contact of the sheet with the deck of the swimming pool. In this way, frictional effects between the cover and the deck are reduced during movement thereof. The bottom surface configuration may adopt any of a variety of forms, including ribs formed on the bottom surface of the sheet, a mesh screen-like substrate secured to the bottom surface of the sheet, or a plurality of projections similar to those of an artificial turf secured to the bottom surface of the sheet, etc.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates in general to certain new and useful improvements in swimming pool covers and, more particularly, to an improved swimming pool cover which is provided with a surface configuration on its underside to reduce frictional effects between the swimming pool cover and a surface with which the cover is in contact.

[0003] 2. Brief Description of the Related Art

[0004] Automatic swimming pool covers have become quite popular in recent years both for purposes of maintaining cleanliness of a swimming pool, maintaining heat in the body of water, and also as a mean of safety. Many automatic swimming pool covers are effective in that they are capable of being walked upon by children so that the incidence of potential drowning is dramatically reduced.

[0005] Generally, all presently available automatic swimming pool covers consist of a fabric sheet, usually formed of a vinyl material, and slidably secured at the sides of the swimming pool in tracks. Automatic pool cover systems are illustrated and described in U.S. Pat. No. 3,060,455 to Joe H. Lamb, U.S. Pat. No. 4,001,900 to Joe H. Lamb, U.S. Pat. No. 4,464,801 to Joe H. Lamb, U.S. Pat. No. 4,939,798 to Harry J. Last, U.S. Pat. No. 3,277,498 to Myron Kleinbard, et al, as well as numerous others.

[0006] In the automatic swimming pool covers, a reel is provided for winding the swimming pool cover upon the reel when the latter is retracted from the body of water in the swimming pool and the fabric is unspooled from the reel when it is desired to cover the body of water in that swimming pool. The drive mechanism for the reel is designed to provide sufficient driving power to enable movement of the swimming pool cover across the pool deck and the body of water in the swimming pool. Due to the fact that the substantial portion of the fabric is pulled across the water surface and the swimming pool cover is effectively supported by that water surface, these automatic pool covers operate quite effectively. The water in the pool actually provides a type of lubricating action and a low friction surface over which the swimming pool cover can be moved.

[0007] In all automatic swimming pool cover systems, it is necessary for a portion of that swimming pool cover, at least at longitudinal edges of the cover, for example, to engage the pool deck as the cover moves back and forth across the swimming pool. This is due to the fact that the tracks which support the edges of the cover are necessarily spaced slightly away from the body of water. In this case, approximately ninety-five percent of the pool cover floats on the pool water surface when moved thereacross.

[0008] Many swimming pool are not rectangular and have a variety of shapes, such as kidney shaped pools and the like. These pools may also be covered with automatic pool covers. As a matter of practicality, the automatic cover is similar to a horizontal blind, in that, coverage of a rectangularly shaped pool is accomplished by superimposing a rectangularly shaped pool cover over the swimming pool. In the case of the non-rectangular swimming pool, a rectangularly shaped pool cover is imposed over this non-rectangular shape. Thus, and in this case, the pool cover side tracks must be mounted on the top of the pool deck surface and necessarily a substantial portion of the pool cover fabric is pulled or dragged across the pool deck.

[0009] It has been well established in the swimming pool industry that when a pool cover fabric is dragged across a pool deck, the amount of force required to retract or extend the cover increased in proportion to the amount of fabric that is dragged across the deck, as opposed to a water surface. If more than thirty-five to forty percent of the fabric is dragged across the pool deck, a severe strain is imposed on the automatic pool cover mechanism almost to the point where it can result in damage if not breakdown of the entire automatic drive system. However, when the deck is wetted, either by rain, splashing of water from the pool onto the deck surface, or from simply opening or closing the cover several times, thereby transferring water from the undersurface of the cover to the deck, the drag force would multiply to the point where the fabric cover could not move and would result in severe damage or a complete breakdown of the automatic drive mechanism. This is due to the surface tension and, in effect, the suction of the wetted fabric to the pool deck.

[0010] Although the frictional effects of dragging a swimming pool cover across a body of water is significantly less than the frictional effects of the dragging the cover across a solid surface, such as a swimming pool deck, the effects arising from pulling movement of the cover across a body of water still exist. Depending upon the size of the body of water, the frictional effects of even moving the swimming pool cover across that body of water can be substantial.

[0011] It has also recently been recognized that one of the ways to overcome this problem of excessive friction between the pool deck and the fabric cover is to utilize a roughened surface on the deck. For example, an artificial turf of the type used in sports fields and the like can be placed on the deck surface in order to reduce surface area contact between the artificial turf and the cover. Other types of carpet-like materials which will serve to break up the surface tension of the water and reduce frictional drag have also been proposed. Generally, it is known that the smoother the pool deck surface, the more severe is the surface tension resulting in suction or sticking of the fabric to the deck.

[0012] One of the major problems with these artificial coverings, such as an artificial turf, is the fact that these artificial turfs can become very slippery and hazardous when wetted. Moreover, even if strategically placed, mats of artificial turf or other material to reduce surface tension can be a hazard from tripping or the like. Furthermore, the use of an artificial turf or similar ground covering is frequently objectionable to the pool owner because of the poor esthetics provided.

[0013] There have been proposals to introduce air beneath the fabric in order to lift the pool cover fabric from the surface of the swimming pool deck. This can be accomplished by adding an additional mechanical device to introduce air underneath the edges of the swimming pool cover and thereby attempt to raise the cover slightly off of the deck to ride on an air cushion. However, this usually results in substantial construction work resulting in substantial expense and the installation of additional mechanical devices. Another way to provide this reduced frictional effect is to employ perforated pipes slightly below the surface of the swimming pool deck to thereby also provide an air cushion. However, again this results in substantial additional cost of construction and, moreover, has only been found to be marginally effective.

OBJECTS OF THE INVENTION

[0014] It is, therefore, one of the primary objects of the present invention to provide a swimming pool cover which has a surface texture such that it is capable of reducing the frictional effects created by movement of the swimming pool cover across the body of water in a swimming pool.

[0015] It is another object of the present invention to provide a swimming pool cover of the type stated which has a roughened surface configuration on its underside to reduce surface area contact between the swimming pool cover and the deck surface when the swimming pool cover is moved thereacross.

[0016] It is an additional object of the present invention to provide a swimming pool cover of the type stated having a lower surface constructed such that only a relatively small surface area of that lower surface resides in contact with a surface on which the swimming pool cover is moved to thereby substantially reduce friction therebetween.

[0017] It is also an object of the present invention to provide a swimming pool cover of the type stated having elements depending from the lower surface which engage a surface across which the swimming pool cover is moved to thereby permit surface friction generation only between the surface on which the cover is moved and the elements on the undersurface of the cover.

[0018] It is a further object of the present invention to provide a swimming pool cover of the type stated which can be manufactured at a relatively low cost and which is highly effective in operation in reducing the amount of force imposed on an automatic drive mechanism.

[0019] It is another salient object of the present invention to provide a method of moving a swimming pool cover across a surface and simultaneously reducing the amount of frictional force which would otherwise be generated during movement of that swimming pool cover across the surface.

[0020] With the above and other objects in view, our invention resides in the novel features of form, construction, arrangement and combination of parts and components presently described and pointed out in the claims.

BRIEF SUMMARY OF THE INVENTION

[0021] The present invention relies upon a non-smooth surface on the underside of the swimming pool cover. In effect, the bottom surface of the fabric has a surface configuration which is roughened in order to substantially reduce surface area contact of the swimming pool sheet with the deck during movement thereof. In this way, the problems of the swimming pool cover sticking to the deck have been overcome. In effect, the texturing or other surface effect to the underside of the swimming pool cover sheet creates a separation in the liquid on the deck or on the underside of the sheet to break surface tension and prevent the suction created by the liquid between the underside of the fabric cover and the swimming pool deck.

[0022] The present invention relates to a swimming pool cover capable of being pulled across a surface with reduced generation of frictional force between the undersurface of the cover and the surface on which the swimming pool cover is moved. In accordance with this invention, the swimming pool cover is provided with a plurality of depending elements on its undersurface which engage the surface on which the cover is moved and without allowing the undersurface of the cover itself to engage a surface on which the cover is moved. In other words, if the swimming pool cover is moved across a deck, only the elements on the undersurface of the swimming pool cover will be in contact with the deck and not the major undersurface area of the cover itself. This will, of course, substantially reduce the frictional force which might otherwise be generated.

[0023] The undersurface of the swimming pool cover of the invention is actually textured in such a way so as to create the depending elements which engage a surface on which the cover is pulled and thereby reduce the amount of surface frictional force which might otherwise be generated.

[0024] The elements which are formed on the undersurface of the sheet may adopt a variety of forms. One of the preferred constructions uses a grid pattern of depending elements, such as, for example, a rectangular array of ribs. Thus, and in this way, only the lower depending edges of the ribs reside in contact with the surface on which the cover is moved. The ribs may be of a regular rectangular shape or a diamond shape, or the like. In another embodiment, the depending elements may adopt the form of a plurality of spaced apart fingers which engage the surface on which the cover is moved. This similarly will reduce the frictional effects which would otherwise arise. In substance, any of a number of desired surface configurations may be employed, such that the depending elements ride on the surface across which the cover is moved and thereby eliminate frictional contact between the major undersurface area of the cover and the surface on which the cover is moved.

[0025] The elements which depend from the undersurface of the swimming pool cover are preferably integrally formed with the cover in the formation of the cover. For this purpose, any of a number of plastic forming operations may be used. Frequently, swimming pool covers are formed of a vinyl material and, in which case, the projections on the undersurface, such as the depending elements, can be formed in a plastic molding operation. The cover may also be formed of one or more layers of material and, in this case, the depending elements would be formed on that layer which resides in contact with the surface on which the cover is moved. The exact technique for producing the elements on that layer would depend upon the material of construction thereof.

[0026] This invention possesses many other advantages and has other purposes which may be made more clearly apparent from a consideration of the forms in which it may be embodied. These forms are shown in the drawings forming a part of and accompanying the present specification. They will now be described in detail for purposes of illustrating the general principles of the invention. However, it is to be understood that the following detailed description and the accompanying drawings are not to be taken in a limiting sense.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Having thus described the invention in general terms, reference will now be made to the accompanying drawings in which:

[0028]FIG. 1 is a schematic top plan view of a typical swimming pool configuration along with an automatic pool cover assembly designed to cause extension and retraction of a pool cover over the swimming pool;

[0029]FIG. 2 is a schematic side elevational view showing a corner portion of the fabric swimming pool cover raised and partially turned over in order to illustrate a surface configuration on the underside thereof in accordance with the present invention;

[0030]FIG. 3 is a side elevational view, similar to FIG. 2, and showing a corner portion raised and partially turned over of a modified form of pool cover in accordance with the present invention;

[0031]FIG. 4 is a sectional view showing a portion of the swimming pool cover of FIG. 3;

[0032]FIG. 5 is a fragmentary perspective view of the underside of a modified form of swimming pool cover in accordance with the present invention;

[0033]FIG. 6 is a bottom plan view of the swimming pool cover of FIG. 5, showing a rib construction on the undersurface thereof; and

[0034]FIG. 7 is a fragmentary perspective view showing the underside of still a further modified form of pool cover using a mesh fabric on the undersurface in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] Referring now in more detail and by reference characters to the drawings, P designates a conventional swimming pool which, in the illustrated embodiment, has somewhat of a kidney shape or other irregular shape. Although most swimming pools are of a rectangular construction, many have an irregular shape, such as that shown in FIG. 1, particularly when the swimming pool is located in a private dwelling structure.

[0036] Provided for use with the swimming pool P, as shown in FIG. 1, is a swimming pool cover assembly 20. This assembly typically is provided with a pair of side rails or tracks 22 located to carry the swimming pool cover 24 across the swimming pool, either when extending same or retracting same. The swimming pool cover 24 is typically rolled upon a spool (not shown) and driven back and forth by means of a drive mechanism 26. This overall construction of moving the swimming pool cover is conventional and is shown in several of the previously mentioned U.S. patents.

[0037] The swimming pool cover of the present invention is comprised of a flexible and foldable and rollable fabric material which may be, for example, a plastic sheet material or a cloth material. In many cases, plasticized cloth material is employed. However, the exact material used in the formation of the pool cover is not critical in accordance with the present invention. The swimming pool fabric cover sheet 24 is typically provided with an upper or top surface 28, as well as a bottom surface 30, as best shown in FIG. 2. The bottom surface of the swimming pool cover is provided with a plurality of depending elements located to move upon a surface over which the swimming pool cover is pulled. These elements may adopt any of a plurality of different forms, as hereinafter described, providing a lower surface configuration which precludes the major portion of the undersurface of the swimming pool cover from coming into contact with the surface over which the cover is moved.

[0038] Any type of undersurface configuration which reduces surface area contact with the swimming pool or the swimming pool deck or similar surface and which thereby reduced frictional effects which would otherwise arise can be employed. This undersurface configuration is also effective to eliminate suction which is sometimes created between a smooth undersurface of a fabric swimming pool cover and a swimming pool deck, particularly when the undersurface of the cover or the upper surface of the deck has been wetted.

[0039] One form of textured bottom surface of a swimming pool cover is shown in FIG. 3 and which comprises a section of an artificial turf on its underside. Thus, by reference to FIGS. 3 and 4, it can be observed that the fabric cover 24 is formed of a sheet 32 which is the outer sheet and a lower substrate 34. In the embodiment as shown in FIGS. 3 and 4, the sheet is inverted in its normal position with respect to FIG. 4. Thus, the sheet 32 has a bottom surface 36 upon which the substrate 34 is secured. This substrate 34 may be secured to the bottom surface 36 of the sheet 32 by any conventional means, such as adhesives, plastic welding, stitching or the like.

[0040] The substrate 34 is provided with a plurality of outwardly extending projections 38, which in a normal artificial turf, simulates grass blades. In this case, the projections 38 are highly effective in that they substantially reduce surface contact between the undersurface of the fabric pool cover 24 and the upper surface of the deck.

[0041]FIGS. 5 and 6 illustrate another embodiment of a fabric cover 40 comprising a rollable and flexible sheet 42, which also has a relatively smooth upper surface 44 and a bottom surface 46. The sheet in FIGS. 5 and 6 is inverted in position, such that the bottom surface 46 appears upwardly presented.

[0042] The sheet 42 is provided on its bottom surface 46 with a textured surface configuration 48 which, in this embodiment of the invention, comprises a plurality of ribs 50. These ribs may be integrally formed with the sheet 42, particularly where the latter is formed of a plastic material. The ribs 50 are only slightly spaced above the bottom surface 46 of the sheet 42 so as to again reduce the surface contact with the pool deck. It can be seen that with the textured surface configuration 48, only a relatively small surface area contact exists when compared to the overall area of the bottom surface 46.

[0043]FIG. 7 illustrates another modified form of fabric pool cover 60 and which is also shown in an inverted position. In this case, the pool cover 60 is comprised of a flexible and foldable and rollable sheet 62, having a relatively smooth upper surface 64 and a bottom surface 66. Secured to the bottom surface 66 is another fabric having a mesh-like sheet construction 68. This sheet 68 of the mesh fabric could be formed of the same material as the sheet 62 or it can be formed of a different material. Moreover, the sheet 68 may be secured to the sheet 62 by any conventional means as, for example, those means for securing the substrate 34 to the sheet 32, as previously described.

[0044] The mesh construction of the fabric sheet 68 is also effective to reduce area surface contact between the fabric pool cover and the surface of the pool deck, in the same manner as in the previous embodiments. It should be observed in this respect that any form of textured surface which reduces surface area contact will also reduce the frictional effects in the area which could otherwise cause a vacuum between the pool cover and the deck surface and is thus contemplated within the present invention.

[0045] Thus, there has been illustrated and described a unique and novel swimming pool cover construction which meets and fulfills all of the objects and advantages which have been sought. It should be understood that many changes, modifications, variations and other uses and applications which will become apparent to those skilled in the art after considering the specification and the accompanying drawings. Therefore, any and all such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention. 

Having thus described the invention, what we desire to claim and secure by letters patent is:
 1. A swimming pool cover for extension and retraction over a swimming pool and where the cover may engage a portion of a deck surrounding the swimming pool during movement thereof, said swimming pool cover comprising: a) flexible swimming pool cover sheet formed of a material capable of being rolled and unrolled; b) said sheet having a top surface and a bottom surface; and c) a surface configuration on said bottom surface of said sheet which is textured to substantially reduce surface area contact of the cover sheet with the deck of the swimming pool during movement thereof to thereby reduce frictional effects between the cover and the deck.
 2. The swimming pool cover of claim 1 further characterized in that said surface configuration is formed on the bottom surface of said sheet.
 3. The swimming pool cover of claim 1 further characterized in that said surface configuration is formed of a separate substrate which is secured to said bottom surface of said sheet.
 4. A swimming pool cover for extension and retraction over a swimming pool and where the cover may engage a portion of a deck surrounding the swimming pool during movement thereof, said swimming pool cover comprising: a) flexible swimming pool cover sheet formed of a material capable of being rolled and unrolled; b) said sheet having a top surface and a bottom surface; and c) a lower surface configuration on said bottom surface of said sheet which is comprised of downwardly projecting ribs on said bottom surface, such that substantially the ribs contact the pool deck, as opposed to the bottom surface of said sheet during movement thereof to reduce frictional effects between the pool deck and the sheet.
 5. A swimming pool cover for extension and retraction over a swimming pool and where the cover may engage a portion of a deck surrounding the swimming pool during movement thereof, said swimming pool cover comprising: a) flexible swimming pool cover sheet formed of a material capable of being rolled and unrolled; b) said sheet having a top surface and a bottom surface; and c) a mesh screen-like substrate on said bottom surface of said sheet providing a lower surface configuration to reduce surface area contact of the bottom surface of the sheet with the deck during movement thereof to thereby reduce frictional effects between the pool deck and the sheet.
 6. A swimming pool cover for extension and retraction over a swimming pool and where the cover may engage a portion of a deck surrounding the swimming pool during movement thereof, said swimming pool cover comprising: a) flexible swimming pool cover sheet formed of a material capable of being rolled and unrolled; b) said sheet having a top surface and a bottom surface; and c) a substrate on said bottom surface of said sheet having a plurality of downwardly extending projections which form a lower surface configuration, such that only the projections engage the deck to reduce area contact of the bottom surface of the sheet with the pool deck during movement thereof to thereby reduce frictional effects between the pool deck and the sheet.
 7. The swimming pool cover of claim 1 further characterized in that said lower surface configuration is flexible so as to be capable of being rolled with said pool cover sheet.
 8. The swimming pool cover of claim 1 further characterized in that said top surface of said sheet is generally smooth.
 9. An improvement in a rollable fabric swimming pool cover of the type which extends over and retracts from its extended position over a swimming pool and which may engage a portion of a swimming pool deck during movement thereof, said improvement comprising: a) a textured surface configuration on a bottom of said swimming pool cover to reduce surface area contact of the swimming pool cover with the deck of the swimming pool during movement thereof and to thereby reduce frictional effects between the swimming pool cover and a swimming pool deck.
 10. The improvement in the rollable fabric swimming pool cover of claim 9 further characterized in that said textured surface configuration is integral with the bottom surface of said swimming pool cover.
 11. The improvement in the rollable fabric swimming pool cover claim 9 further characterized in that the improvement comprises a separate substrate secured to the underside of rollable fabric swimming pool cover and which contains a textured surface configuration thereon.
 12. The improvement in the rollable fabric swimming pool cover of claim 9 further characterized in that the improvement comprises downwardly projecting ribs on the bottom surface of said fabric cover, such that the ribs substantially contact the pool deck, as opposed to the bottom surface of the fabric pool cover, during movement thereof.
 13. The improvement in the rollable fabric swimming pool cover of claim 9 further characterized in that the improvement comprises a mesh-like substrate on the bottom surface of said sheet providing a surface configuration to reduce surface contact of the bottom surface of the pool cover with a pool deck.
 14. The improvement in the rollable fabric swimming pool cover of claim 9 further characterized in that the improvement comprises a bottom surface configuration on said pool cover with a plurality of outwardly extending projections, such that only that the projections engage the swimming pool deck to reduce area contact therewith.
 15. The improvement in the rollable fabric swimming pool cover of claim 9 further characterized in that the improvement comprises a lower flexible surface configuration which is flexible as to be capable of being rolled with said pool cover sheet.
 16. A method of reducing frictional effects between a flexible and rollable swimming pool cover and a swimming pool deck when a swimming pool cover is removed across the deck to cover the swimming pool or retracted from a covering position over the swimming pool, said method comprising: a) mounting said swimming pool cover in a pair of tracks which allow movement across said swimming pool; and b) providing a textured surface configuration on the bottom surface of said swimming pool cover to reduce surface area contact of the swimming pool cover with the deck of the swimming pool during movement thereof to thereby reduce frictional effects between the swimming pool cover and the deck of the swimming pool. 